The present invention generally relates to an air compressor. More particularly, the present invention pertains to an air compressor of the air pressure type that is used in a vehicular height adjusting device.
A known air compressor is disclosed in, for example, Japanese Patent Laid-Open Publication No. Hei 9-250507 published on Sep. 22, 1997. This air compressor includes a cylinder head comprised of a housing and a cover plate. The housing forms the valve seats of a suction valve and a discharge valve, and accommodates the suction valve and the discharge valve. The cover plate closes an upper opening edge of the housing. The housing is fixed against the cylinder by a fixing member which engages the cover plate so as to touch an opening edge of the cylinder.
In the above-mentioned air compressor, it is necessary to exchange or use a different housing to change the structure of the suction valve, to change the opening-pressure of the discharge valve or to change the characteristic of the air compressor by tuning the diameters of the suction port of the suction valve and the discharge port of the discharge valve. However, from a cost standpoint, this is quite undesirable because the housing is generally the largest member amongst the various members forming the cylinder head and is relatively expensive.
In light of the foregoing, a need exists for an air compressor which allows various aspects of the compressor such as those mentioned above to be changed in a relatively cost-effective manner.
One aspect of the present invention involves an air compressor that includes a cylinder head accommodating a suction valve and a discharge valve, a cylinder having an open end closed by the cylinder head, a piston slidably positioned within the cylinder and forming a variable volume chamber with the cylinder head, and a driving device for driving the piston in a reciprocating manner. The cylinder head includes a plate forming a valve seat and a suction port of the suction valve, and a valve seat and a discharge port of the discharge valve. The cylinder head also includes a housing accommodating the suction valve, the discharge valve and the plate, with the plate being fixed against the cylinder by a fixing member so that the plate confronts the opening end of the cylinder.
This construction of the air compressor is quite advantageous from the standpoint of cost because the housing does not need to be exchanged to change the structure of the suction valve, to change the opening-pressure of the discharge valve or to change the characteristic of the air compressor by tuning the diameters of the suction port of the suction valve and the discharge port of the discharge valve. Rather, with the present invention, these changes can be accomplished by exchanging the plate which forms a much smaller and less expensive part of the cylinder head.
According to another aspect of the present invention, an air compressor includes a housing and a plate forming a cylinder head, with the plate being provided with a suction port forming part of a suction valve and a discharge port forming part of a discharge valve. A cylinder has an open end that is closed by the cylinder head. A first seal member is positioned to provide a seal between the plate and the housing while a second seal member is positioned to provide a seal between the plate and the cylinder. A fixing member fixes the cylinder head to the cylinder. A piston is slidably positioned in the cylinder and forms a variable volume chamber with the cylinder head, and a driving device is operatively connected to the piston to drive the piston in a reciprocating manner.
In accordance with another aspect of the invention, an air compressor includes a housing and a plate forming a cylinder head, with the plate being provided with a suction port and a suction valve seat, and being provided with a discharge port and a discharge valve seat. A suction valve member is accommodated on the plate and is positionable in engagement with the suction valve seat to close the suction port and is movable out of engagement with the suction valve seat to open the suction port. A discharge valve member is positioned within the cylinder head and is positionable in engagement with the discharge valve seat to close the discharge port and is movable out of engagement with the discharge valve seat to open the discharge port. A cylinder has an open end that is closed by the cylinder head and a fixing member fixes the cylinder head to the cylinder. A piston is slidably positioned in the cylinder and forms a variable volume chamber with the cylinder head. A driving device is operatively connected to the piston to move the piston within the cylinder.